A population pharmacokinetic model using allometric scaling for baricitinib in patients with juvenile idiopathic arthritis

Abstract Baricitinib is approved for the treatment of rheumatoid arthritis (RA) in more than 70 countries, and juvenile idiopathic arthritis (JIA) in the European Union. Population pharmacokinetic (PK) models were developed in a phase 3 trial to characterize PK in pediatric patients with JIA and identify weight‐based dosing regimens. The phase 3, randomized, double‐blind, placebo‐controlled withdrawal, efficacy and safety trial, JUVE‐BASIS, enrolled patients (aged 2 to